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joschum
November 24th, 2008, 08:22 PM
Hello,

I installed Ubuntu 8.10 (intrepid) on a Lenovo ThinkPad T43p. I can connect via WLAN but after some minutes the connection breaks. The connection works fine on another ThinkPad (X300) so the access point should not be the source of the problem. After being disconnected a window pops up which is entitled "Wireless Network Authentication Required". When I click on the connect button the connection is sometimes restored but it might take a long time. Does anybody have an idea how to achieve a stable WLAN connection?

Hoping for help,
joschum

Here are the details of my wireless configuration:


root@thalamus:~# lspci -nn | grep -i net
02:00.0 Ethernet controller [0200]: Broadcom Corporation NetXtreme BCM5751M Gigabit Ethernet PCI Express [14e4:167d] (rev 11)
0b:02.0 Ethernet controller [0200]: Atheros Communications Inc. AR5212 802.11abg NIC [168c:1014] (rev 01)


root@thalamus:~# egrep -v "^$|^#" /etc/network/interfaces
auto lo
iface lo inet loopback


root@thalamus:~# egrep -v "^$|^#" /etc/resolv.conf
nameserver 195.186.1.109
nameserver 195.186.4.109


root@thalamus:~# egrep -v "^$|^#" /etc/hosts
127.0.0.1 localhost
127.0.1.1 thalamus
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

After the connection is broken ifconfig yields:


ath0 Link encap:Ethernet HWaddr 00:14:a4:39:42:f3
inet6 addr: fe80::214:a4ff:fe39:42f3/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:127 errors:0 dropped:0 overruns:0 frame:0
TX packets:225 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:13885 (13.8 KB) TX bytes:38001 (38.0 KB)

... and after reconnecting


ath0 Link encap:Ethernet HWaddr 00:14:a4:39:42:f3
inet addr:192.168.254.100 Bcast:192.168.254.255 Mask:255.255.255.0
inet6 addr: fe80::214:a4ff:fe39:42f3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:248 errors:0 dropped:0 overruns:0 frame:0
TX packets:427 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:26796 (26.7 KB) TX bytes:70582 (70.5 KB)
...

wifi0 Link encap:UNSPEC HWaddr 00-14-A4-39-42-F3-30-30-00-00-00-00-00-00-00-00
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:204578 errors:0 dropped:0 overruns:0 frame:17256
TX packets:1743 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:199
RX bytes:21907654 (21.9 MB) TX bytes:157070 (157.0 KB)
Interrupt:21


root@thalamus:~# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.38.0 0.0.0.0 255.255.255.0 U 0 0 0 vmnet8
172.16.51.0 0.0.0.0 255.255.255.0 U 0 0 0 vmnet1
192.168.254.0 0.0.0.0 255.255.255.0 U 2 0 0 ath0
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 ath0
0.0.0.0 192.168.254.1 0.0.0.0 UG 0 0 0 ath0


root@thalamus:~# iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

vmnet1 no wireless extensions.

vmnet8 no wireless extensions.

pan0 no wireless extensions.

wifi0 no wireless extensions.

ath0 IEEE 802.11g ESSID:"zup-wlan" Nickname:""
Mode:Managed Frequency:2.437 GHz Access Point: 00:15:E9:11:5F:64
Bit Rate:48 Mb/s Tx-Power:8 dBm Sensitivity=1/1
Retry:off RTS thr:off Fragment thr:off
Encryption key:19FD-0EE4-F98C-7337-B0B8-288F-3410-68DB Security mode:restricted
Power Management:off
Link Quality=43/70 Signal level=-55 dBm Noise level=-98 dBm
Rx invalid nwid:201808 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0